This invention relates to a communication and control system, and more particularly to a distributed supervisory control and data acquisition ("SCADA") system.
A SCADA communication and control system is a wide area network of remote terminal units communicating by short bursts at the 900 MHz radio frequency range. The remote terminal units are, e.g., power control stations used by a utility company for controlling power distribution over a specific area. A typical SCADA system 10 is shown in FIG. 1, including a master controller 12 coupled to a master radio unit 14 via modem 16 and microwave link 18. Messages from the master controller 12 are sent to the master radio 14 for broadcast to multiple remote terminal units 22. By including only one master radio 14, however, the network communication distances are limited, especially in rugged terrain. Further, by using telephone-type modems 16, acquisition times are relatively slow. Accordingly, there is a need for systems having enhanced range and throughput.